This application pertains to the art of tie wraps and, more particularly, to tie wraps of the type including an elongated toothed strap extending from a head having a passage through which the strap is receivable. The invention is particularly applicable to tie wraps which cannot be released after the strap is extended through the head. However, it will be appreciated that certain features of the invention have broader aspects and can be used on tie wraps of other types.
Nonreleasable tie wraps are commonly used for security purposes because it is necessary to break the tie wrap in order to free the items held thereby and this provides a ready indication as to whether or not the held devices have been tampered with. For example, it is common to use tie wraps of this type for holding lids on containers. The tie wrap passes through aligned holes on the lid and container, and the tie wrap must be broken for allowing opening of the lid. Tie wraps of the type described are commonly constructed with one or more pawls positioned in a strap receiving passage in a head from which a toothed strap extends. Insertion of the strap through the head passage in one direction provides locking cooperation between the pawls and teeth for preventing retraction of the strap. Therefore, it is necessary to break the strap in order to release same. In tie wraps of this type, the strap can be inserted through the head passage in an opposite incorrect direction and the pawls will loosely grip the teeth for retaining the strap in its position extending through the head passage. However, there is no locking cooperation between the pawls and teeth, and withdrawal of the strap is readily accomplished simply by pulling on same. It would be desirable to have an arrangement for preventing inadvertent or intentional false latching of a strap through a head passage by preventing insertion of the strap through the head passage in an improper direction.